Examine source code of NewTab Pastels

{
  "name": "NewTab Pastels",
  "version": "2.6",
  "description": "A Pastel New Tab Page.",
  "manifest_version": 2,
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "permissions": [
    "theme"
  ],
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4b402447-69d7-4362-8888-9d53e185f441}"
    }
  }
}